Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 82: Topological Insulators II (joint session TT/MA)

TT 82.7: Talk

Thursday, March 15, 2018, 11:00–11:15, A 053

Magnetotransport properties of 3D topological insulator (TI) nanowire structures — •Kristof Moors¹, Peter Schüffelgen^2,3, Daniel Rosenbach^2,3, Tobias Schmitt², Thomas Schäpers^{2, 3}, and Thomas Schmidt¹ — ¹University of Luxembourg, Luxembourg, Luxembourg — ²Peter Grünberg Institut, Jülich, Germany — ³Helmholtz Virtual Institute for Topological Insulators (VITI), Jülich, Germany

3D TIs host gapless spin-momentum locked surface states with great potential for applications in spin electronics or quantum computing. When confined to the surface of a straight nanowire however, a confinement-induced gap appears and the topological protection is lost. Interestingly, this protection can be restored by a magnetic field with a half-integer magnetic flux piercing the cross section of the wire. To further explore the magnetotransport properties of nanowire structures, e.g. kinks or Y-junctions, we present a 3D tight-binding model, based on the k · p Hamiltonian introduced by Zhang. This model allows us to study structures made of different TI materials with a potentially anisotropic and/or particle-hole asymmetric surface state spectrum. Based on band structure and ballistic transport simulations, we demonstrate a rescaling of the magnetoconductance oscillations as a function of the surface state thickness, the protection of gapless surface states from a perpendicular magnetic field and special angles of the magnetic field for which nanowire kinks and Y-junctions feature conductance resonances. These properties could be relevant in future quantum transport experiments of TI nanowire structures.